Two-dimensional metastructured film with Titanium Oxide is fabricated as a photo-catalytic photoanode with exceptional visible light absorption. Credit: Copyright UNIST
A new multilayered (Au NPs/TiO2/Au) photoelectrode boosts ability of solar water-splitting to produce hydrogen. According to the research team, this special photoelectrode, inspired by the way plants convert sunlight into energy is capable of absorbing visible light from the sun, and then using it to split water molecules (H2O) into H2, O2.
This multilayered photoelectrode takes the form of 2D hybrid metal-dielectric structure, which mainly consists of 3 layers of gold (Au) film, ultrathin TiO2 layer (20 nm), and gold nanoparticles (Au NPs). They reported that this promising photoelectrode shows high light absorption of about 90% in the visible range 380-700 nm, as well as significant enhancement in photo-catalytic applications.
Many structural designs, eg hierarchical and branched assemblies of nanoscale materials have been suggested to increase the UV-visible absorption and to enhance water-splitting efficiency. However, through incorporation of plasmonic metal nanoparticles (i.e. Au) to TiO2 structures, their photoelectrodes have shown to enhance the photoactivity in the entire UV-visible region of solar spectrum when compared to the existing ones, the team reports.
Prof. Jeong Min Baik of UNIST (School of Materials Science and Engineering) states, “Several attemps have been made to use UV-based photoelectrodes for hydrogen production, but this is the first time to use the metal-dielectric hybrid-structured film with TiO2 for oxygen production.” This special type of photoelectrode uses ~95% of the visible spectrum of sunlight, which makes up a substantial portion (40%) of full sunlight. He adds, “The developed technology is expected to improve hydrogen production efficiency.”
Prof. Heon Lee (Korean University) states, “This metal-dielectric hybrid-structured film is expected to further reduce the overall cost of producing hydrogen, as it doesn’t require complex operation processes.” He continues by saying, “Using nanoimprint lithography, mass production of hydrogen will be soon possible.”
Prof. Baik adds, “This simple system may serve as an efficient platform for solar energy conversion, utilizing the whole UV-visible range of solar spectrum based on two-dimensional plasmonic photoelectrodes.” http://news.unist.ac.kr/10662/
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